Forming apparatus



P 22, 19164 D. G. DE VLIEG ETAL 3,149,596

FORMING APPARATUS Filed June 13, 1961 2 Sheets-Sheet 2 F IG. 3

INVENTORS DONALD G. DEVLIEG EARL L. CHRISTIAN 3'1 RNEY AGENT UnitedStates Patent 3,149,596 FQRMING APPARATUS Donald Gerard De Vlieg, LaMesa, and Earl Landon Christian, 31in Diego, Calif, assignors to GeneralDynamics Corporation, San Diego, (Ialifl, a corporation of DelawareFiled June 13, 1961, Ser. No. 116,860 2 Claims. ((15. 11344) Thisinvention relates generally to forming apparatus and more particularlyto forming apparatus capable of forming sheet metal blanks by theapplication of pressure to the blanks.

It is an object of the present invention to provide novel apparatuscapable of forming blanks rapidly and accurately.

It is another object of the invention to provide novel apparauts whichgenerates pressure to accurately form blanks.

It is a further object of the invention to provide novel apparatus whichgenerates pressure having uniform distribution to form blanks.

It is still a further object of the invention to provide novel apparatuswhich generates pressure having uniform distribution and applies thepressure directly to blanks to be formed.

It is another object of the invention to provide novel forming apparatuswhich forms blanks with very little material thinning of the formedpart.

Other objects, advantages and capabilities of the invention will becomeapparent from the following description, taken in conjunction with theaccompanying drawings in which:

FIGURE 1 is a pictorial view in perspective of the forming apparatusarranged for use with a blow imparting device.

FIGURE 2 is a vertical central section through the forming apparatus,showing the movable die separated from the stationary die and carryingthe sheet metal blank to be formed and the draw ring.

FIGURE 3 is the same as FIGURE 2, except that the movable die and theparts carried thereby have been inserted in the stationary die such thatthey rest upon the deformable material in the stationary die.

FIGURE 4 is the same as FIGURES 2 and 3 with the forming of the sheetmetal blank completed; and

FIGURE 5 is a perspective view of the sheet metal blank in its formedstate such as may be produced in the practice of this invention.

Similar reference numerals refer to like parts throughout the severalviews.

Referring to the drawings, and particularly to FIG- URES 1 and 2, theforming apparatus of the present invention is generally indicated by thenumeral 8 and consists of a stationary die 10 adapted to be positionedon a base member 11, and a movable die 12 adapted to face the forceimparting member 13 of a high energy actuator, for example, of the typerevealed in Patent No. 2,979,938 and issued to Jack B. Ottestad.

The stationary die 10 is generally outwardly cylindrical in shape andhas an aperture 14 also generally cylindrical in shape with a bottom 16and mouth 18. A fluid passage 20 is provided in the stationary diemember for interconnecting the aperture with the outside of the diemember, and is located intermediate the bottom 16 and mouth 18. Adeformable material 22, which has perfect fluidity, prefably a liquid,such as water, is positioned in the aperture 14, and has a level 23 justbelow the fluid passage 20.

The movable die 12 has an outer surface configuration conforming to theshape of the aperture 14 as to provide a close slip-fit between it andthe stationary die member when inserted in the aperture, as shown, forexample, in

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FIGURES l and 2. An annular seal 24 positioned in a suitable groove inthe outer surface of the movable die 12 provides sealing between thedies. The movable die has a workingsurface which comprises a cavity 26and a flat portion 28 surrounding the cavity. The cavity 26 is shown asbeing hemispherical in shape for illustration purposes, but it is to beunderstood that it could assume any desired shape to be imparted to ablank to be formed. To provide for the escape of air from the cavity 26during the forming operation, a fluid passage 30 in the movable die 12interconnects the cavity with a plurality of radial grooves 31 in theupper surface of the movable dies.

A sheet metal blank 32 is adheringly positioned on the flat portion 28of the movable die 12 as to cover the cavity by means of a film 34 ofheavy lubricator material, such as grease, or the like. Another film 36of like lubricator material adheres a plate member or draw ring 38 tothe blank 32 such that an orifice 40 in the draw ring exposes theportion of the blank 32 covering the cavity 26. The draw ring 38conforms to the shape of the aperture 14, as to be insertable thereinalong with the movable die 12 and blank 32, as shown in FIGURE 3. Thefilm 34, in addition to adhering the blank 32 to the movable die 12,also provides lubrication and sealing therebetween during the formingoperation, as will hereinafter be more fully described. In like mannerthe film 36 also provides lubrication between the blank and the platemember 38.

In the operation of the device of the present invention, the movable die12 carrying the blank 32 and plate member 38 is inserted into theaperture 14 and allowed to settle into and float on the liquid 22. Asthe movable die travels into the aperture first air, and then excesswater is expelled through the fluid passage 20. .When water ceases toflow through the fluid passage 20, the parts are positioned as showninFIGURE 3.

Referring to FIGURE 4, when a blow is applied to the movable member 12by the member 13, the movable die and its associated parts are furtherforced into the liquid 22 to produce a uniformly distributed hydraulicpressure which acts on the blank directly through the orifice 40 toforce it into the cavity 26 wherein it assumes the shape of the cavity,as shown in FIGURES 4 and 5. During this rapid forming action, pressureis maintained on the draw ring 38 which prevents the edge of the blank32 from wrinkling as it is drawn into the cavity 26, and also preventsthe edge from bending and allowing water to be forced between the blankand the draw ring into the cavity.

The films 34 and 36 greatly aid the forming action by facilitating thesliding of the blank 32 between the movable die 12 and the draw ring 38as it is drawn into the cavity 26, which results in very little materialthinning of the formed part. The film 34 also establishes a seal betweenthe blank and the movable member, thus preventing the Water 22 fromentering the cavity 26, which would result in a malformed part. Any backpressure which would be developed by air trapped in the cavity 26 as theblank is forced into the cavity is allowed to bleed ofr through thefluid passage 30 and radial grooves 31, thus also insuring a properlyformed part.

Although a specific embodiment of the invention has been described andillustrated in detail, it is to be clearly understood that the same isby way of illustration and example only; it is to be understood that theinvention is not limited thereto, as many variations will be readilyapparent to those versed in the art and the invention is to be given itsbroadest possible interpretation within the terms of the appendedclaims.

What is claimed is:

1. Forming apparatus comprising a first member having an aperture, fluidpassage means interconnecting said aperture with the outside of saidfirst member, said fluid passage means being located intermediate themouth and bottom of said aperture, a plate member having an orifice, asecond member having a cavity, said second member conforming to saidaperture and having a close slipfit therebetween, means for venting saidcavity, and means for adhering said plate member and a blank to beformed on said second member to cover said cavity and expose a portionof the blank through said orifice, said plate memher and second memberbeing positionable within said aperture and supportable on a liquid insaid aperture to contact the blank portion with the liquid through saidorifice, said first and second members being relatively movable forurging the liquid through said orifice to force the blank into saidcavity to assume the shape of said cavity.

2. Forming apparatus comprising a stationary die mem her having anaperture,'fluid passage means interconnecting said aperture with theoutside of said stationary die member, said fiuid passage means beinglocated intermediate the mouth and bottom of said aperture, a platemember having an orifice, a movable die member having a cavity, saidmovable die member conforming in close slip-ifi-t With said aperturemeans for venting said cavity, a first film of lubricator material foradhering a blank to be formed on said movable die member to cover saidcavity, a second film of lubricator material for adhering said platemember to the blank to expose the portion of the blank covering saidcavity through said orifice, said plate member and movable die memberbeing positionable within said aperture and supportable on a liquid insaid aperture to contact the blank portion with the liquid through saidcavity, said movable die member being movable into said aperture forurging the liquid through said orifice to force the blank into saidcavity to assume the shape of said cavity.

References Cited in the file of this patent UNITED STATES PATENTS696,821 Huber Apr. 1, 1902 2,199,627 French et al. May 7, 1940 2,284,773Sivian et al. June 2, 1942 2,354,005 Flowers July 18, 1944 2,649,067Kranenberg Aug. 18, 1953 2,969,758 HoWlett et al Jan. 31, 1961 FQREIGNPATENTS 603,683 Great Britain June 21, 1948 650,747 Great Britain Feb.28, 1951

1. FORMING APPARATUS COMPRISING A FIRST MEMBER HAVING AN APERTURE, FLUIDPASSAGE MEANS INTERCONNECTING SAID APERTURE WITH THE OUTSIDE OF SAIDFIRST MEMBER, SAID FLUID PASSAGE MEANS BEING LOCATED INTERMEDIATE THEMOUTH AND BOTTOM OF SAID APERTURE, A PLATE MEMBER HAVING AN ORIFICE, ASECOND MEMBER HAVING A CAVITY, SAID SECOND MEMBER CONFORMING TO SAIDAPERTURE AND HAVING A CLOSE SLIPFIT THEREBETWEEN, MEANS FOR VENTING SAIDCAVITY, AND MEANS FOR ADHERING SAID PLATE MEMBER AND A BLANK TO BEFORMED ON SAID SECOND MEMBER TO COVER SAID CAVITY AND EXPOSE A PORTIONOF THE BLANK THROUGH SAID ORIFICE, SAID PLATE MEMBER AND SECOND MEMBERBEING POSITIONABLE WITHIN SAID APERTURE AND SUPPORTABLE ON A LIQUID INSAID APERTURE TO CONTACT THE BLANK PORTION WITH THE LIQUID THROUGH SAIDORIFICE, SAID FIRST AND SECOND MEMBERS BEING RELATIVELY MOVABLE FORURGING THE LIQUID THROUGH SAID ORIFICE TO FORCE THE BLANK INTO SAIDCAVITY TO ASSUME THE SHAPE OF SAID CAVITY.